Fetch data from entry with particular key from JSON array with jq

Question

How do we fetch the email from the entry whose level key has the value 2 from the below JSON document?

The expected output is

[email protected]

Any suggestion, please?

{
  "escalation_policy": {
    "on_call": [
      {
        "level": 2,
        "start": "2022-05-25T00:30:00Z",
        "end": "2022-05-25T09:30:00Z",
        "user": {
          "id": "ABOKC",
          "name": "Jaavena Dobey",
          "email": "[email protected]",
          "time_zone": "Tokyo"
        }
      },
      {
        "level": 7,
        "start": "2022-05-23T01:00:00Z",
        "end": "2022-05-30T01:00:00Z",
        "user": {
          "id": "KLSPSP",
          "name": "kosls frank",
          "email": "[email protected]",
          "time_zone": "Tokyo"
        }
      },
      {
        "level": 3,
        "start": "2022-05-23T01:00:00Z",
        "end": "2022-05-30T01:00:00Z",
        "user": {
          "id": "SKSPSLSL",
          "name": "Smitha Choudhary",
          "email": "[email protected]",
          "time_zone": "Tokyo"
        }
      }
    ]
  }
}

Answer 1

Like this,

1. Get the array of the objects.
2. Select the ones where level is 2
3. Of the array returned, print the user's email

Invocation and output,

$ jq ".escalation_policy.on_call[] | select( .level == 2) | .user.email" test.json
"[email protected]"

Answer 2

The following gets one of the email addresses of the people on call, namely the first one with an escalation policy on call level equal of 2:

jq -r '.escalation_policy.on_call | map(select(.level == 2)) | first.user.email' file

You didn't ask for this specifically, but the following gives you the email address of the on-call person with the lowest .level. We do this by sorting the on_call array and returning the .user.email value from the entry that sorts first:

jq -r '.escalation_policy.on_call | sort_by(.level) | first.user.email' file

We could also make sure that the current time is within the .start and .end timestamps. We do this by selecting only the relevant on-call entries before sorting them as before:

jq -r '
    .escalation_policy.on_call |
    map(select( now > (.start|fromdate) and now < (.end|fromdate) )) |
    sort_by(.level) | first.user.email' file

We can do this because we're lucky enough to have dates in exactly the format that the fromdate function in jq expects.